See-through head mounted displays (HMD) enable displays of computer-generated images on a display medium mounted a few inches in front of the eyes of a HMD-wearing user. A HMD may be incorporated into a pair of glasses or a helmet worn by the users. A user may view videos, receive information, and interact with a display with minimal obstruction to the user's field of view of the real world. HMDs are increasingly being found in augmented-reality devices. See-through HMDs may be monocular or stereoscopic. A monocular HMD displays a single image of the display. On the other hand, a stereoscopic HMD displays an object stereoscopically by projecting a left-eye and a right-eye image of the object independently to create a perception of depth to the user. The stereo separation of the left-eye and right-eye images may be increased or decreased to project the digitally projected images at a specific depth plane.
Frequently, however, a HMD-wearing user may focus on a depth plane not coinciding with the depth plane at which the currently displayed images are being projected. When this happens, eye separation artifacts between the left-eye and the right-eye images may be perceptible, leading to a double vision effect. For example, if an image such as an user interface (UI) element is stereoscopically projected at a depth plane of three feet, but the user is focusing on infinity while walking, the UI element may appear doubled and out of focus. Such a double vision effect is not only unpleasant but may also lead to eye strain or fatigue, thereby detracting from the overall experience of the HMD-wearing user. As such, there is a need for a solution to mitigate the double vision effect experienced by HMD-wearing users when the users focus on a depth plane different from the one at which stereoscopic images are being projected.